feat: 用户管理直接开通/撤销商业认证

- 用户列表每行加💼按钮，未认证点击开通，已认证点击撤销
- 新增 /api/business-grant/{id} 端点
- 开通/撤销时通知用户

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/main.py

@@ -614,6 +614,21 @@ def reject_translation(sid: int, user=Depends(require_role("admin"))):
     return {"ok": True}
 
 
+@app.post("/api/business-grant/{user_id}")
+def grant_business(user_id: int, user=Depends(require_role("admin"))):
+    conn = get_db()
+    conn.execute("UPDATE users SET business_verified = 1 WHERE id = ?", (user_id,))
+    target = conn.execute("SELECT role, display_name, username FROM users WHERE id = ?", (user_id,)).fetchone()
+    if target:
+        conn.execute(
+            "INSERT INTO notifications (target_role, title, body, target_user_id) VALUES (?, ?, ?, ?)",
+            (target["role"], "🎉 商业认证已开通", "管理员已为你开通商业用户认证，现在可以使用商业核算等功能。", user_id)
+        )
+    conn.commit()
+    conn.close()
+    return {"ok": True}
+
+
 @app.post("/api/business-revoke/{user_id}")
 def revoke_business(user_id: int, body: dict = None, user=Depends(require_role("admin"))):
     conn = get_db()